Apparatus and method for crushing and segregating materials



March 17, 1942.

M, ovEsTRup 2,276,333 APPARATU AND METHOD FOR CRUSHING AND SEGREGATI NGMATERIALS Filed Dec. 14, 19:59 2 sheets-s eet 1 Nay/Iv 0023772410 March17, 1942.' M. OVESTRUD 2,276,333

APPARATUS AND MliTl-IOD FOR CRUSHING AND SEGREGATING MATERIALS FiledDec. 14, 1959 2 sheets'sheet 2 II J 1 4 7 k MELVIN Ovsarzw s'ra'rasAPPTUS AND METHOD FOR CRUSHHVG AND SEGREGATING MATER s Melvin Ovestrud,Minneapolis, assignmto Pioneer Enging Works, c., apolis, Minn, acomration ofimeiaware Application December It, 1939, Serial No. 309,204

8 Claims. (ill. 83-93) This invention relates generally to an improvedOutput of aggregate. A further object is to proapparatus and method forcrushing stone, rock vide an improved crushing method making posandsimilar materials and segregating the crushed sible the better handlingand crushing of the m material in desired sizes. te al and particularlysuited to the production of The invention particularly aims to providean such chips in the quantity desired. improved apparatus and method forthe provision These and other more detailed and specific obof a crushedstone aggregate for use in the conjects will be disclosed in the courseof the followstruction and maintenance of highways. In work logspecification, reference being bad to the acupon highways of the kindhaving a hard surface companying drawings, in whichcomposed of a mixtureof bituminous or asphaltic Fig. 1 is a diagrammatic view of a crushingoils and crushed stone aggregate it has been plant showing the essentialcrushing and conveyfound that one of the very important component ingelements thereof and with my invention in ingredients is a speciallyprepared and sized corporatedtherein.

crushed rock aggregate known popularly under Fig. 2 is an enlargedvertical cross se tion the name of chips. These chips are mad by tothrough the screen assembly used in screening crushing the rock to acomparatively small size, out the various sizes of materials, this viewbeing so that, for example, the chips will pass a screen t ken ppr ximaely 0n the line 2- -2 in Fig. 3.

having one-half inch square openings but will Fig.3 is an enlarged sideelevation of the main b retained upon a screen having one-quarterportion of the plant, with a side fragment broken inch square openings.The resulting material out to show interior construction.

when used on th highways has the very desirable In describing myinvention reference will first features of increasing traction andoffering bet- 'be had to the diagrammatical showing of Fig. 1 tervisibility as is commonly appreciated. in which reference character Adesignates 2.

However, in the construction of such highways, frame and B the wheelsupon which said frame is particularly in regions remote from rock orgravel 2 supported for transport purposes. crushing plants, it has beenfound very costly to Supported on the frame A is a large deliverypurchase the required chips. Even though the and mixing hopper 5 whichclumps at its open construction or maintenance project may have lowerend 6 into a side delivery conveyor 1 for carin operation at the site aportable rock crushing ryingoff the crushed aggregate. Above the largeplant of the usual type, the cost of producing such upper end of thehopper is mounted a vibratingchips is prohibitive. This is due, first,to the fact screen unit in which a total of three and one-half that thetightening down of all crushing elements decks or screens are provided,all of said screens of the plant so retards production that theoperbeing, in the assembly here shown, inclined ation cost, per ton ofchips, is very high; and seclengthwis or endwise to cause the materialto ond,-to the fact that the very nature of the chips travel towardstheir lowermost ends, although requires that all material of less sizethan, for exsaid screens may be horizontal if desired. ample,one-quarter inch, must be screened out The lower full deck or screen 8is the initial reand wasted. This loss or wasta e in actual pracceivingdeck for the raw material, which is tice amounts to the order offorty-five Percen Of dumped upon the upper end of the deck by a contheactual material. The net resultissuchahigh veyor 9 leading from thegravel pit or feeding cost of production that the chips are usuallyhopper t h course, by any other bought from some remote plant WhereSpecial suitable feeding means. This deck is preferably q p e s used, orwhere ey 9 as a made of square mesh screen having a mesh size Product,and here the final cost 13 Q5 selected to pass the largest particles orrocks dehigh due to the relative scarcity and the transp sired in theaggregate and such particles, as well tation req ir as all smaller ones,will therefore fall through gg figgg gifg g g gg fi fif g gg: 1 thisdeck and directly into the hopper 5 effectin ducing a percentage ofchips as a concomitant of the first separatmn of the materialthe regularcrushing operation and production, A sand screen or lower half deck I0is arranged and at the same average cost as the regular agin the Screenbelow the pper end portion gregate used m such highway work Another ofthe deck 8 and is of fine trash to pass only ject is to provide a meansfor producing such Small nd particles and divert all larger parchips ina portable crushing plant and in any ticles off its lower end itno thehopper. Sand reasonable desired quantity relativetothe normal Passed ythis c een "I is diverted by an adjustable wing or gate ll out from anend of the hopper to a side delivery sand conveyor l2.

The material rejected by the raw material receiving deck 8 is carriedoff the lower end thereof by an inclined chute I3 to a substantiallycentrally located primary jaw crusher ll of conventional form, and thematerial is therefore reduced to smaller size by action of this crusher.Such material then falls from the jaw crusher M to a conveyor l5 whichcarries it upwardly in a direction away from the hopper 5, to a pointover the end of the frame A, the material being thenunit. This deck l8has screens of two differentsizes, the upper end section l9 having meshopenings, for example one-half inch square to pass material of themaximum size desired for chips, and the lower end section 20 havingopenings of substantially the same size as those in the deck 8 to passmaterial of the maximum size required in the aggregate.

Material rejected by this deck I8 is caused to flow by gravity off thelower end and over an inclined chute 2| which leads to a conventionalsecondary roll crusher 22 located over the conveyor IS. The material is'thus further comminuted and is returned by conveyors l5 and Ho to theupper deck I8 for final separation. Properly correlated adjustments ofthe jaw and roll crushers l4 and 22, which adjustments may be made whilethe machine is in operation, will efiect the necessary'relative stage ofreduction in each, to the point that all material recirculated to thescreens will be finally passed out to the various delivery conveyors.

The chip size material passed by the upper end section 19 of the upperdeck l8 iallsto an intermediate deck 23 in which is incorporated, belowsaid section I9, a fines removing screen 24 of one-quarter inch mesh,for example, and which is thus adapted to pass all of the material ofless size than the minimum required for the chips.

These fines drop to the raw material receiving deck 8 through which theypass into the hopper 5, as a component part of the delivered aggregate.

The material rejected by the screen 26, all of, chip size, is divertedby a bailie 25 through a side delivery port 26 to a chute 2'5 whichleads down alongside the hopper 5 to a chips conveyor 28 delivering thematerial laterally, as shown.

The material passing through the lower section 20 of the upper deck l8falls upon a blank section on platform 29 of the intermediate deck 23,,from which it is diverted laterally through of the material is caused topass through more than one screen and all screens work constantly atmaximum effectiveness.

- Under most circumstances the amount of chips required in the work is asmall part of the total volumetric quantity output of the machine. Thisworks as an advantage in that the production of the chips, as aby-product of the machine, will not remove too much of the componentmaterial of chip size required in the aggregate. Only oneport 26 andspout 21 are shown in the drawings, and the amount of chips deliveredmay be varied by use of a damper 32 in the spout as shown in Fig. 2 ifso desired, the material, as this damper is opened, being diverted tofiow through a fork 27a of the spout back to the hopper through port21b. However, it is obvious that delivery spouts for the chips may beused at each side of the screen unit if so desired.

The apparatus thus described permits the practice of a new method in thecrushing and separation of stone and like material. This involvesfeeding the raw material onto a lower screen deck of a mesh sizesuitable to pass the largest particles required, screening out frombeneath this lower deck a variable portion of the fine material or sand,conducting the material rejected by the lower deck to a primary jaw.crusher for initial crushing, returning such jected by the finesremoving screen for use as after at least one crushing operation hastaken to the maximum size required in the crushed product and carryingthem by a by-pass means beneath the lower deck for mixing and delivery,conducting all particles rejected by the upper deck to a secondary .rollcrusher for further crushing, and finally recirculatingthese crushedparticles to the upper receiving deck. This method of crushing,screening, circulating and recirculating the material, aside fromadvantages such as the full use of all screens, balanced load on therespective crushers, and other features, also is of extreme advantage inthe production of chips since the chip size material is screened out atsubstantially a mid point in the entire operation after at least onecrushing operation has taken place. Thus material of chip size in theraw material will always be carried into the final aggregate mixture toretain the proper relative component sizes in the aggregate. Then placea separation is made to remove chip size material and deliver a variablequantity thereof for use. There are thus at all times two full screendecks producing finished material with a side ports 30 to by-passductsil leading the material to the hopper 5 below'the deck'B.

The general operation of the machine will be readily apparent from theforegoing, and it will be appreciated that the crushed materialdelivered to the hopper 5 through the various screens will be of theproper mixture required for highway construction and repair. Therelative sand content may be varied as required by adjusting portion ofone deck producing, if desired, the chip size product with separatedelivery means. Referring particularly to Figs. 2 and 3, the

mechanical assembly of the machine will be described in more detail, themachine shown being one of practical construction and well adapted toillustrate my invention. The hopper 5 is supported on the frame A withsuitable supporting parts and frame members. designated generally at 33.The various screen decks as heretofore described are arranged in ascreen unit 34 which is placed in the frame over the hopper 5 and whichis given a vibratory motion by any suitable and well known operatingmeans (not shown). The jaw crusher l4 and roll crusher 22 are arrangedin the assembly in substantially the positions shown, and are of theconventional conlaterally arranged to deliver the materials out to theside of the machine. Conveyor 9 is shown as being also of theconventional belt type and may be driven as indicated at 31 from drivingparts of the machine, this conveyor of course being inclined upwardlyfrom the'pit or other l2, and 28 for aggregate,.

feeding point. The return and recirculating conveyors l5 and 1511 are'of the belt type. the first receiving material from both the jawcrusher I4, guided by the short pan 35, and the roll crusher 22, anddelivering to .the lower end of'the second through a chute l5. Saidchute is of course latuct rejected in this screening, screening thecrushed product to remove therefrom material of chip size andsmaller,screening out said last mentioned fines from said chip size crushedmaterial, and separately delivering the chip size material independentlyof the aggregate and chip size material resulting from .the firstscreening.

3. The method of crushing and screening rock to provide an ag regate andchips of substantially uniform size smaller than the maximum size ofsaid aggregate, which comprises initially screening the rock to removetherefrom both the material of aggregate size and any material of chipsize in said rock, crushing the rejected rock, screening the crushedrock to first remove material of chip size, and smaller, and then toremove material of larger size within the range of sizes required in theaggregate, screening out the lines from the crushed chip size material,separately to and with theaggregate and erally or angularly extendedsince the conveyors l5-I5u. operate alongside each other, and thedelivery chute ii is similarly inclined to lead the material properlyback to the screen unit as. Suitable supporting framework (A' in Fig. 1)is provided for outer ends of the conveyors l5-l5a and the chute i6.Inspection of upper working parts is provided for by provision of aplatform 39, steps 45 and railings M in accordance with usual practicein such machines.

The sand gate H is adjustable from the side of the hopper by means of alever 42 connected to the rock shaft as of said gate and working over aquadrant it as shown.

The screen unit 35 has spaced side panels or members :35 between whichthe screens or decks are mounted as shown in Fig. 2, and the chipdelivery port 26 is formed in one of these side members with the spout21 slidably embracing flanges 25a around said port in the manner clearlyshown. The by-pass ducts 3| are also secured on these side members 55over ports therein and are extended downwardly alongside the screen unitloosely into flared portions 30!: of the hopper to conduct allproduct-sized material from the upper deck to the hopper.

It is understood that suitable modifications may be maue in thestructure as disclosed, pro-' vided such modifications come within thespirit and scope of the appended claims. Having now therefore fullyillustrated and described my invention, what I claim to be new anddesire to protect by Letters Patent is:

l. The method of crushing and separating rock material, which includesthe steps of initially screening the material to remove particles of allsizes less than a selected maximum, crushing the material rejected in.this step of the method, screening the crushed material separately fromthe first screening step to remove a product of substantially uniformsize less than the maximum resulting from said initial screening step,screening out the fines from said product and joining them with thesmaller sized material of the first screening, and finally deliveringsaid product separate from all other materials.

' 2. The method of crushing and screening a rock product to provide anaggregate and chips of a substantially uniform size smaller than thelargest of said aggregate. which comprises screening the rock product toremove particles of both aggregate and chip size, crushing the rockproddelivering the chip size material secured after crushing, andconducting and mixing the. said fines and the said material of largersize directly chips secured by the initial screening 4. In a rockcrushing and screening apparatus,

a conveyor for raw materials, a screen unit hav-' ing a ma n screen forreceiving material from the conveyor and screening out materials of anaggregate size, means for crushing material rejected by the main screen,an u per screen arranged over the main screen, means for-returningcrushed material to said upper screen, the said up r screen havingopenings in one portion for removing chips of a size smaller than thelargest particles of the aggregate, and said upper screen also havingopenings in another portion for removing particles of size suitable forthe use in the aggregate, an intermediate screen having openings in oneportion for removing fines from the chips and having an imperforate por=tion for receiving the larger material of aggregate size from the upperscreen, means for delivering the chip size material from theintermediate screen independently of the aggregate, and means forconducting the aggregate passed by the upper screen around the mainscreen for admixture with the aggregate passed by said main screen.

5. In a rock'crushing and screening apparatus, a conveyor for the rawmaterial, a screen unit having three large and one small superimposedscreens therein, the lower larger screen of said unit being adapted atone end to receive material from the conveyor and separate out particlesof aggregate size, the small screen being disposed beneath said lowerscreen for removing a portion of the sand-like particles from theaggregate, means for crushing material rejected by the lower screen,means for returning said crushed material to the uppermost large screenof the screen unit, the said upper screenhaving openings in the portionreceiving the crushed material for passing "screen, means for separatelydelivering chip-size material from the intermediate screen, and meansfor conducting aggregate size material from the intermediate screen formixing with the material passed by the lower screen.

6. A rock crushing and screening apparatus for screening out material ofaggregate size and a smaller material for use as chips, comprising ascreen unit having a plurality of screens, means for conducting the rockfirst over one screen for removing an aggregate including material ofchip size as a component part, means for crushing material rejected inthe first screening, means for conducting said crushed materials overanother screen, independently of the movement of material over saidfirst mentioned screen, for first removing material of chip size andsmaller and then removing larger material for use in the aggregatepassed by the first screen, means for screening out the fines from thecrushed chip size material and returning them to the first mentionedscreen, means for separately delivering the crushed chip size materialafter the fines are removed therefrom, and means beneath the screenpassing the crushed material larger than chip size for bypassing thismaterial around the first mentioned screen and mixing it with thematerial of aggregate size.

7. A rock crushing and screening apparatus for separating an aggregateand a smaller chip size material from a raw rock material, comprising ascreen unit having a plurality of screens, means for first conductingthe raw material over one screen for separating out an aggregate whichincludes material oi chip size as a component part, means for c rawmaterial rejected by the screen, means for conducting the crushedmaterial over another ofvsaid screens for separating out material ofchip size and smaller, means for screening out tliefines from said chipsize material, means for separately delivering the chip size materialafter the fines are removed, means for returning the fines from the chipsize material to the aforesaid aggregate, and means for screening outaggregate size material from the crushed material subsequent to removalof the chip size material therefrom.

8. The method of treating rock material to produce an aggregateofparticles heterogeneously sized up to a predetermined maximum and aseparate supply of particles of substantially uni-' 7 form size butsmaller than such maximum, which gate size and delivering said uniformlysized particles separately, the balance of said crushed material of asize not greater than said predetermined maximum being returned to thematerial forming said aggregate mass to be comingled therewith.

MELVIN OYES'I'RUD.

